Thursday, May 03, 2012

Eventual Sunshine

This morning's shower and thunderstorm activity is on its way through -- having dropped varying amounts of rainfall based on location but some spots to our south have picked up some decent amounts as the bulk of heavier activity has tracked across Delaware and South Jersey so far. The 5 AM temp and radar map above shows most of this is south of the city at this point and its trajectory of east-southeast will continue to push it through the south side of the region over the next several hours...probably off the coast by 9 AM.

Today's forecasting challenge -- not that the last few days have been walks in the park, mind you -- is how quick the low clouds and marine influence in place over us gets shoved out of here thanks to an approaching warm front that currently lies across West-Central Pennsylvania. This front will continue to lift northeast and should cross the region later on today. This will result in gradual brightening and more sunshine taking over as we move into the afternoon. The higher resolution NAM (optimistic and aggressive on temperatures for today) has this brightening taking place between 10 and 11 AM...if that happens, we will end up warmer than our projections of mid 70's in Philadelphia. I'm thinking with the extra stability thrown in from this morning's rains that it might be midday or just after that for us to clear out -- it will result in a warmer afternoon, especially later on, but it might be tough to get to 80. We'll see. The slower the clearing though, the lower the high will ultimately be. It will be cooler at the Shore -- probably 60's for a late day high -- than it will be inland and west.

A few scattered thunderstorms may develop this afternoon or evening out to our west and move through parts of the region this evening or tonight. These aren't likely and it's dependent on sunshine breaking out fast enough to destabilize the atmosphere.